RF switches are used in a variety of RF circuits to implement various functions. For instance, an RF system using different signaling methods over different frequencies may be implemented by using a network of antenna switches to select from between different types of RF front-end circuits. One example of such a circuit is a multi-standard cellular telephone that can make calls using different standards such as code division multiple access (CDMA) or Global System for Mobile Communications (GSM). By using an RF switch, an RF front end circuit optimized for CDMA communication may be used for CDMA calls, while an RF front-end circuit optimized for GSM communication may be used for GSM calls. In addition, RF switches may be used to implement adjustable matching networks for antennas and power amplifiers, and to provide adjusting tuning for high frequency filters by switching in and out and/or bypassing passive matching and tuning elements.
As the number of bands supported by multi-standard cellular handsets increases, there is a corresponding increase in the number of switches, filters, amplifiers and matching networks and supporting routing used to implement the front ends of such handsets. In some cases, these components may be implemented using multichip modules that house several integrated circuits, RF filters, and passive components. Some of the technical challenges involved in the design of such multi-standard systems and multichip modules that support such systems is the routing of connection lines in a way that takes into consideration performance issued caused by cross coupling between connection lines, isolation and attenuation that may degrade RF performance.